The art has put in practical use an automatic steering parking assist system configured to cause a monitor mounted inside a vehicle to display a view rearwardly of the vehicle body and to effect an automatic steering with utilization of an electrically powered steering (EPS) as an actuator. A journal of Society of Automotive Engineers of Japan includes a thesis introducing such system, entitled: “Development of Intelligent Parking Assist” (Non-Patent Document 1). According to this thesis, a driver, after switching the shift lever into reverse, uses buttons shown on a touch panel of a monitor to effect setting of e.g. a mode of parking, a parking target position, etc. Specifically, the mode of parking, whether a garage parking or a parallel parking is selected by a selection button on the touch panel. Then, the user will adjust the parking target position shown in a superposed manner on the monitor and then finally presses an OK button on the touch panel to start the parking assist.
When the driver effects adjustment and confirmation of parking target position with using the touch panel on the monitor, if the amount of adjustment is large, it will take a considerable time period before start of assist, that is, start of parking assist, thus impairing the advantage of using the parking assist system. Then, in the case of the technique disclosed Non-Patent Document 1, attempts are made for improvement of the precision in the initial position of the parking target position, through recognition of parking stall delimiting lines by an image processing or recognition of a space available for parking with using a supersonic sensor.